Lubricants, Greases and Aqueous Fluids Containing Additives Derived from Dimercaptothiadiazole Polymers

ABSTRACT

The present invention relates to the composition comprising an oil of lubricating viscosity and a mixture of at least one dimercaptothiadiazole polymer or derivative thereof; and at least one carboxylic acid. These products generally show an ability to improve antiwear (including extreme pressure) and corrosion properties in lubricants.

FIELD OF THE INVENTION

This invention relates to lubricants, greases and aqueous fluids containing additives which are derived from cyclic organic compounds which contain nitrogen and sulfur atoms in the ring structure.

BACKGROUND OF THE INVENTION

Lubrication involves the process of friction reduction, accomplished by maintaining a film of a lubricant between surfaces which are moving with respect to each other. The lubricant prevents contact of the moving surfaces, thus greatly lowering the coefficient of friction. In addition to this function, the lubricant also can be called upon to perform heat removal, containment of contaminants, and other important functions.

Since lubricants for different uses must operate under different conditions, numerous additives have been developed to establish or enhance various properties of lubricants. Representative types of additives which are used include viscosity improvers, detergents, dispersants, antioxidants, extreme pressure additives, corrosion inhibitors and several others. Very frequently, combinations of additive types are required. In addition, certain additives can have more than one function in a lubricant.

Of particular importance in many applications are antiwear agents, many of which function by a process of interaction with the surfaces, thereby providing a chemical film which prevents metal-to-metal contact under high load conditions. Wear inhibitors which are useful under extremely high lead conditions are frequently called “extreme pressure agents.” Extreme pressure agents have a very high affinity for surfaces, particularly metal surfaces (with which many of these agents actually chemically react), and are frequently selected from the following chemical types: zinc organodithiophosphates; sulfurized carboxcylic acids; chlorinated waxes; amine salts of phosphate esters; phosphites; and others. Certain of these materials, however, must be used judiciously in certain applications due to their property of accelerating corrosion of metal parts, such as bearings. In addition, some applications require very low concentrations of certain elements, such as phosphorus, which restricts the utility of otherwise quite useful extreme pressure agents.

U.S. Pat. No. 2,764,547 to Fields describes compounds which can be added to lubricants for the purpose of inhibiting the corrosion of silver-containing metal parts. These compounds are prepared by reacting 2,5-dimercapto-1,3,4-thiadiazole with an unsaturated cyclic compound containing at least about 5 carbon atoms. Examples of suitable cyclic compounds are: dipinene; pinene; alpha-methyl styrene; and styrene. The compounds are used to control the corrosion of silver which is normally exhibited by sulfur-containing detergent additives for lubricating oil.

Richardson et al, in U.S. Pat. No. 2,799,651, teach compounds which are related to those of the foregoing patent, and which are also useful as corrosion inhibitors for silver and similar metals. These inhibitors are prepared by reacting 2-mercapto-4-phenyl-5-thionel,3,4-thiadiazole with an carboxcylic acidic compound, a sulfonyl chloride, or, after chlorinating the thiadiazole, with a mercaptan. As with the compounds of the preceding patent, the reaction products are typically used in conjunction with sulfur- or phosphorus containing detergent additives for lubricating oils.

U.S. Pat. No. 3,840,549, issued to Blaha et al relates to preparation of 2-hydrocarbyldithio-5-mercapto-1,3,4-thiadiazoles. These compounds are prepared by reacting 2,5-dimercapto-1,3,4-thiadiazole with any member of the class of 2,5bis(hydrocarbyldithio)-1,3,4-thiadiazole in the presence or absence of a solvent.

SUMMARY OF THE INVENTION

The present invention relates to the composition comprising (A) an oil of lubricating viscosity and (B) a reaction product of (i) at least one dimercaptothiadiazole polymer or derivative thereof; and (ii) at least one carboxcylic acid, or salt of the reaction product. These reaction products generally show an ability to improve antiwear, antiweld, extreme pressure, and corrosion inhibiting properties of lubricants, and greases.

DETAILED DESCRIPTION OF THE INVENTION

The term “hydrocarbyl” includes hydrocarbon as well as substantially hydrocarbon groups. Substantially hydrocarbon describes groups which contain hetero atom substituents which do not alter the predominantly hydrocarbon nature of the group.

Examples of hydrocarbyl groups include the following:

(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, aromatic-, aliphatic- and alicyclic-substituted aromatic substituents and the like as well as cyclic substituents wherein the ring is completed through another portion of the molecule (that is, for example, any two indicated substituents may together form an alicyclic radical);

(2) substituted hydrocarbon substituents, that is, those substituents containing nonhydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon nature of the substituent; those skilled in the art will be aware of such groups (e.g., halo (especially chloro and fluoro), hydroxy, mercapto, nitro, nitroso, sulfoxy, etc.);

(3) hetero atom substituents, that is, substituents which will, while having a predominantly hydrocarbon character within the context of this invention, contain an atom other than carbon present in a ring or chain otherwise composed of carbon atoms (e.g. alkoxy or alkylthio). Suitable heteroatoms will be apparent to those of ordinary skill in the art and include, for example, sulfur, oxygen, nitrogen and such substituents as, .e.g., pyridyl, furyl, thienyl, imidazolyl, etc. In general, no more than about 2, preferably no more than one, hetero substituent will be present for every ten carbon atoms in the hydrocarbyl group. Typically, there will be no such hetero atom substituents in the hydrocarbyl group. Therefore, the hydrocarbyl group is purely hydrocarbon.

The present invention is based, in part, upon an additive for lubricants which is (A) the reaction product of (i) a dimercaptothiadiazole polymer and (ii) an carboxcylic acid, or salt thereof.

(i) Mercaptothiadiazoles

Thiadiazoles, which are cyclic compounds in which the ring contains 2 nitrogen, 2 carbon, and 1 sulfur atoms, are discussed by W. R. Sherman, “The Thiadiazoles,” in Heterocyclic Compounds, Volume 7, R. C. Elderfield, Editor, John Wiley & Sons, Inc., New York, pages 541-626, 1961; the synthesis and properties of many thiadiazoles are described in this reference. The dimercaptothiadiazoles which are particularly useful in this invention have formulae as follows: ##STR1## The compound which is most readily available and particularly preferred for purposes of the present invention, is 2,5Dimercapto-1,3,4-thiadiazole polymer, sometimes referred to herein as “DMTDPP.” It should be understood, however, that the term DMTDPP, as used herein, can encompass any of the dimercaptothiadiazole polymers or mixtures of two or more dimercaptothiadiazole polymers.

(ii) Carboxcylic Acids

Carboxcylic acids which are useful in the invention include branched or unbranched hydrocarbons which contain a non-aromatic double bond, that is, a double bond connecting two aliphatic carbon atoms. In one embodiment, the carboxcylic acids are monocarboxcylic acidic compounds. In another embodiment, the carboxcylic acids are terminal monocarboxcylic acidic compounds (mono-1-carboxcylic acids or alpha carboxcylic acids).

Carboxcylic acidic compounds containing up to about 50 carbon atoms are suitable for reaction with DMTDP. In one embodiment, the carboxcylic acids contain from about 3, or about 6 to about 30, or to about 16 carbon atoms.

In one embodiment, these carboxcylic acids are alpha-carboxcylic acids (sometimes referred to as mono-l-carboxcylic acids) or isomerized alpha-140 carboxcylic acids.

Commercially available alpha-carboxcylic acid fractions that can be used include the C.sub.15-18 alpha-carboxcylic acids, C.sub.12-16 alpha-carboxcylic acids, C.sub.14-16 alpha-carboxcylic acids, C.sub.1418 alpha-145 carboxcylic acids, C.sub.16-18 alpha-carboxcylic acids, C.sub.16-20 alpha-carboxcylic acids, C.sub.22-28 alpha-carboxcylic acids, etc.

Isomerized alpha-carboxcylic acids are alpha-carboxcylic acids that have been converted to internal carboxcylic acids. The isomerized alpha-carboxcylic acids suitable for use herein are usually in the form of mixtures of internal carboxcylic acids with some alpha-carboxcylic acids present. The procedures for isomerizing alpha-carboxcylic acids are well known to those in the art. Briefly these procedures involve contacting alpha-carboxcylic acid with a cation exchange resin at a temperature in a range of about 80.degree. to about 130.degree. C. until the desired degree of isomerization is achieved. These procedures are described for example in U.S. Pat. No. 4,108,889 which is incorporated herein by reference. Methods for the synthesis of carboxcylic acids and carboxcylic acid mixtures are very well known in the art, and need not be discussed herein.

(B) The Reaction Products

While it is not desired to be bound to any particular theory, the reaction products of DMTDP and carboxcylic acids are believed to be addition products in which the mercapto sulfur atom bonds to one of the carboxcylic acidic carbon atoms; the mercapto hydrogen atom also attaches to the other carbon. This reaction is described by A. K. Fields, “Addition of 1,3,4-Thiadiazole-2,5-dithiol to Carboxcylic acidic Compounds,” Journal of Organic Chemistry, Volume 21, pages 497499 (1956), which is incorporated herein by reference. Either or both of the mercapto functions in DMTDP can be reacted; thus, depending upon whether a “mono-adduct” or a “bis-adduct” is desired, one mole of DMTDP can be reacted with one or two moles of an carboxcylic acid. Reacting one mole of DMTDP with more than one, but less than two, moles of unsaturated compound will give a mixture of mono- and bis-adducts. In addition, one mole of DMTDP can be reacted with one mole of an carboxcylic acid, then the reaction product can be further reacted with a different carboxcylic acid to give a final product having mixed functionality.

In one embodiment of the invention the reaction product or more compounds having the formula: ##STR2## wherein the two R.sub.1 groups are the same or different and are hydrogen or hydrocarbyl groups, provided that one R.sub.1 group is a hydrocarbyl group. In the above formula, each R.sub.1 may be independently a hydrocarbyl group containing up to 50 carbon atoms. In one embodiment, each R.sub.1 independently contains about 3, or about 6 up to about 30, or to about 16 carbon atoms. Each R.sub.1 is generally derived from one or more of the carboxcylic acids listed above.

Ammonium Salts

Ammonium salts can be formed by reacting ammonia or amines with the DMTDP reaction products. The amines include ammonia, monoamines or polyamines.

The monoamines generally contain from 1 to about 24 carbon atoms, or to about 12, or to about 6. Examples of monoamines useful in the present invention include methylamine, ethylamine, propylamine, butylamine, octylamine, and dodecylamine. Examples of secondary amines include dimethyl amine, diethyl amine, dipropylamine, dibutylamine, methylbutylamine, ethylhexylamine, etc. Tertiary amines include trimethylamine, tributylamine, methyldiethylamine, ethyldibutylamine, etc.

Tert-Aliphatic Primary Amines

In one embodiment, the amine is a tertiary-aliphatic primary amine. Generally, the aliphatic group, preferably an alkyl group, contains from about 4, or about 6, or about 8 to about 30, or to about 24 carbon atoms. Usually the tertiary alkyl primary amines are monoamines represented by the formula alkyl 1-12 ##STR3## wherein R.sub.2 is a hydrocarbyl group containing from one to about 27 carbon atoms and R.sub.2 ′is a hydrocarbyl group containing from 1 to about 12 carbon atoms. Such amines are illustrated by tertiary-butylamine, tertiaryhexylamine, 1-methyl-1-amino-cyclohexane, tertiary-octylamine, tertiary-decylamine, tertiary-dodecylamine, tertiary-tetradecylamine, tertiary-hexadecylamine, tertiary-octadecylamine, tertiarytetracosanylamine, tertiary-octacosanylamine.

Mixtures of amines are also useful for the purposes of this invention. Illustrative of amine mixtures of this type are “Primene 81R” which is a mixture of C.sub.11-C.sub.14 tertiary alkyl primary amines and “Primene JMT” which is a similar mixture of C.sub.18-C.sub.22 tertiary alkyl primary amines (both are available from Rohm and Haas Company). The tertiary alkyl primary amines and methods for their preparation are known to those of ordinary skill in the art. The tertiary alkyl primary amine useful for the purposes of this invention and methods for their preparation are described in U.S. Pat. No. 2,945,749 which is hereby incorporated by reference for its teaching in this regard.

Hydroxylamines

In another embodiment, the amine may be a hydroxylamine. Typically, the hydroxylamines are primary, secondary or tertiary alkanolamines or mixtures thereof. Such amines can be represented by the formulae: ##STR4## wherein each R″ is independently a hydrocarbyl group of one to about eight carbon atoms or hydroxyhydrocarbyl group of two to about eight carbon atoms, preferably one to about four, and R′ is a divalent hydrocarbyl group of about two to about 18 carbon atoms, preferably two to about four. The group —R′—OH in such formulae represents the hydroxyhydrocarbyl group. R′ can be an acyclic, alicyclic or aromatic group. Typically, R′ is an acyclic straight or branched group such as an ethylene, 1,2-propylene, 1,2-butylene, 1,2-octadecylene, etc. group. Where two R″ groups are present in the same molecule they can be joined by a direct carbon-to-carbon bond or through a heteroatom (e.g., oxygen, nitrogen or sulfur) to form a 5-, 6-, 7- or 8-membered ring structure. Examples of such heterocyclic amines include N-(hydroxyl lower alkyl)-morpholines, -thiomorpholines, -piperidines, -oxazolidines, -thiazolidines and the like. Typically, however, each R″ is independently a methyl, ethyl, propyl, butyl, pentyl or hexyl group.

Examples of these alkanolamines include mono-, di-, and triethanolamine, diethylethanolamine, ethylethanolamine, butyldiethanolamine, etc.

The hydroxylamines can also be an ether N-(hydroxylhydrocarbyl)amine. These are hydroxylpoly(hydrocarbyloxy) analogs of the above-described hydroxy amines (these analogs also include hydroxyl-substituted oxyalkylene analogs). Such N-(hydroxylhydrocarbyl) amines can be conveniently prepared by reaction of epoxides with aforedescribed amines and can be represented by the formulae: ##STR5## wherein x is a number from about 2 to about 15 and R″ and R′ are as described above. R″ may also be a hydroxylpoly(hydrocarbyloxy) group.

The amine may also be a polyamine. The polyamine may be aliphatic, cycloaliphatic, heterocyclic or aromatic. Examples of the polyamines include polyamines, hydroxyl-containing polyamines, arylpolyamines, and heterocyclic polyamines.

Alkylenepolyamines

Alkylenepolyamines are represented by the formula ##STR6## wherein n has an average value between about 1, or 2 to about 10, or to about 7, or to about 5, and the “Alkylene” group has from 1, or 2 up to about 10, to about 6, or to about 4.R.sub.3 is independently preferably hydrogen; or an aliphatic or hydroxy-substituted aliphatic group of up to about 30 carbon atoms. In one embodiment, when R.sub.3 is not hydrogen, then R.sub.3 is defined the same as R″ above.

Such alkylenepolyamines include methylenepolyamines, ethylenepolyamines, butylenepolyamines, propylenepolyamines, pentylenepolyamines, etc. The higher homologs and related heterocyclic amines such as piperazines and N-amino alkyl-substituted piperazines are also included. Specific examples of such polyamines are ethylenediamine, triethylenetetramine, tris-(2aminoethyl)amine, propylenediamine, trimethylenediamine, tripropylenetetramine, tetraethylenepentamine, hexaethylene-heptamine, pentaethylenehexamine, etc.

Higher homologs obtained by condensing two or more of the above-noted alkylene amines are similarly useful as are mixtures of two or more of the aforedescribed polyamines.

Ethylenepolyamines, such as some of those mentioned above, are useful. Such polyamines are described in detail under the heading Ethylenediamines in Kirk Othmer's “Encyclopedia of Chemical Technology”, 2d Edition, Vol. 7, pages 22-37, Interscience Publishers, New York (1965). Such polyamines are most conveniently prepared by the reaction of ethylene dichloride with ammonia or by reaction of an ethyleneimine with a ring opening reagent such as water, ammonia, etc. These reactions result in the production of a complex mixture of polyalkylenepolyamines including cyclic condensation products such as the aforedescribed piperazines. Ethylenepolyamine mixtures are useful.

Other useful types of polyamine mixtures are those resulting from stripping of the above-described polyamine mixtures to leave as residue what is often termed “polyamine bottoms”. In general, alkylenepolyamine bottoms can be characterized as having less than two, usually less than 1% (by weight) material boiling below about 200.degree. C. A typical sample of such ethylene polyamine bottoms obtained from the Dow Chemical Company of Freeport, Texas designated “E-100” has a specific gravity at 15.6.degree. C. of 1.0168, a percent nitrogen by weight of 33.15 and a viscosity at 40.degree. C. of 121 centistokes. Gas chromatography analysis of such a sample contains about 0.93% “Light Ends” (most probably diethylenetriamine (DETA)), 0.72% triethylene tetramine TETA, 21.74% tetraethylene pentaamine and 76.61% penmethylene hexamine and higher (by weight). These alkylenepolyamine bottoms include cyclic condensation products such as piperazine and higher analogs of diethylenetriamine, triethylenetetramine and the like.

Condensed Polyamines

Another useful polyamine is obtained by condensing at least one hydroxy compound with at least one polyamine reactant containing at least one primary or secondary amino group. The hydroxy compounds are preferably polyhydric alcohols and amines. The polyhydric alcohols are described below (See carboxylic ester dispersants). Preferably the hydroxy compounds are polyhydric amines. Polyhydric amines include any of the above-described monoamines reacted with an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, etc.) having 2 to about 20 carbon atoms, or to about 4. Examples of polyhydric amines include tri-(hydroxypropyl)amine, tris-(hydroxymethyl) aminomethane, 2amino-2-methyl-1,3-propanediol, N,N,N′,N′-tetrakis(2hydroxypropyl)ethylenediamine, and N,N,N′,N′-tetrakis (2hydroxyethyl)ethyl enediamine, preferably tris(hydroxymethyl)aminomethane (THAM).

Polyamine reactants, which react with the polyhydric alcohol or amine to form the condensation products or condensed amines, are described above. Preferred polyamine reactants include triethylenetetramine (TETA), tetraethylenepentamine CTEPA), pentaethylenehexamine (PEHA), and mixtures of polyamines such as the abovedescribed “amine bottoms”.

The condensation reaction of the polyamine reactant with the hydroxy compound is conducted at an elevated temperature, usually about 60.degree. C. to about 265 degree. C., (preferably about 220 degree. C. to about 250.degree. C.) in the presence of an acid catalyst.

The amine condensates and methods of making the same are described in U.S. Pat. No. 5,053,152 and PCT publication WO 86/05501 which are incorporated by reference for their disclosures to the condensates and methods of making. The preparation of such polyamine condensates may occur as follows: A 4-necked 3-liter round-bottomed flask equipped with glass stirrer, thermowell, subsurface N.sub.2 inlet, Dean-Stark trap, and Friedrich condenser is charged with: 1299 grams of HPA Taft Amines (amine bottoms available commercially from Union Carbide Co. with typically 34.1% by weight nitrogen and a nitrogen distribution of 12.3% by weight primary amine, 14.40 by weight secondary amine and 7.4% by weight tertiary amine), and 727 grams of 40% aqueous tris(hydroxymethyl)aminomethane (THAM). This mixture is heated to 60.degree. C. and 23 grams of 85% H.sub.3 PO.sub.4 is added. The mixture is then heated to 120.degree. C. over 0.6 hour. With N.sub.2 sweeping, the mixture is then heated to 150.degree. C. over 1.25 hour, then to 235.degree. C. over 1 hour more, then held at 230.degree.235.degree. C. for 5 hours, then heated to 240.degree. C. over 0.75 hour, and then held at 240.degree.-245.degree. C. for 5 hours. The product is cooled to 150.degree. C. and filtered with a diatomaceous earth filter aid. Yield: 84% (1221 grams).

Hydroxyl Polyamines

In another embodiment, the polyamines are hydroxyl polyamines. Hydroxyl polyamine analogs of hydroxylmonoamines, particularly alkoxylated alkylenepolyamines (e.g., N,N(diethanol)ethylenediamine) can also be used. Such polyamines can be made by reacting the above-described amines with one or more of the above-described oxides. Similar oxidealkanolamine reaction products can also be used such as the products made by reacting the aforedescribed primary, secondary or tertiary alkanolamines with ethylene, propylene or higher epoxides in a 1.1 to 1.2 molar ratio. Reactant ratios and temperatures for carrying out such reactions are known to those skilled in the art.

Specific examples of alkoxylated alkylenepolyamines include N-(2-hydroxyethyl) ethylenediamine, N,N-bis(2-hydroxyethyl)-ethylenediamine, 1-(2-hydroxyethyl)piperazine, mono(hydroxypropyl)-substituted tetraethylenepentamine, N-(3 -hydroxybutyl)-tetramethylene aliamine, etc. Higher homologs obtained by condensation of the above illustrated hydroxy-containing polyamines through amino groups or through hydroxy groups are likewise useful. Condensation through amino groups results in a higher amine accompanied by removal of ammonia while condensation through the hydroxy groups results in products containing ether linkages accompanied by removal of water. Mixtures of two or more of any of the aforesaid polyamines are also useful.

Heterocyclic Amines

In another embodiment, the amine may be a heterocyclic mono-or polyamine. The heterocyclic amines include aziridines, azetidines, azolidines, tetra- and dihydropyridines, piperidines, imidazoles, diand tetrahydroimidazoles, piperazines, purines, morpholines, thiotnorpholines, N-aminoalkylmorpholines, N-aminoalkylthiomorpholines, N-aminoalkylpiperazines, N,N′-diaminoalkylpiperazines, azepines, azocines, azonines, azecines and tetra-, di- and perhydro derivatives of each of the above and mixtures of two or more of these heterocyclic amines. Preferred heterocyclic amines are the saturated 5- and 6 membered heterocyclic amines containing only nitrogen, oxygen and/or sulfur in the hetero ring, especially the piperidines, piperazines, thiamorpholines, morpholines, pyrrolidines, and the like. Piperidine, aminoalkyl-substituted piperidines, piperazine, amino alkyl-substituted pip erazines, morpholine, aminoalkyl-substituted morpholines, pyrrolidine, and aminoalkyl-substituted pyrrolidines, are especially preferred. Usually the aminoalkyl substituents are substituted on a nitrogen atom forming part of the heterocycle. Specific examples of such heterocyclic amines include N-aminopropyl-morpholine, N-aminoethylpiperazine, and N, N′-diaminoethyl-piperazine. Hydroxy-heterocyclic amines are also useful, for example Nhydroxyethylpiperazine, and the like.

Polyalkene-Substituted Amines

In another embodiment, the amine is a polyalkene-substituted amine. These polyalkene-substituted amines are well known to those skilled in the art. These amines are disclosed in U.S. Pat. Nos. 3,275,554; 3,438,757; 3,454,555; 3,565,804; 3,755,433; and 3,822,289. These patents are hereby incorporated by reference for their disclosure of hydrocarbyl amines and methods of making the same.

Typically, polyalkene-substituted amines are prepared by reacting carboxcylic acids and carboxcylic acid polymers (polyalkenes) with amines (mono- or polyamines). The amines may be any of the amines described above. Examples of these compounds include poly(propylene)amine; N,N-dimethyl-N-poly(ethylene/propylene)amine, (50:50 mole ratio of monomers); polybutene amine; N,N-di(hydroxyethyl)N-polybuteneamine; N-(2-hydroxypropyl)-N-poly(butene)amine; N-poly(butene)aniline; N-poly(butene)morpholine; N-poly(butene)ethylenediamine; N-poly(propylene)trimethylenediamine; N-poly(butene)diethylenetriamine; N′,N′-poly(butene)tetraethylenepentamine; N,N-dimethyl-N′-poly(propylene)1,3-propylenediamine and the like.

The polyalkene is characterized as containing from at least about 8 carbon atoms, or at least about 30, or at least about 35 up to about 300, or to about 435 200, or to about 100 carbon atoms. In one embodiment, the polyalkene is characterized by an Mn (number average molecular weight) value of at least about 500. Generally, the polyalkene is characterized by an Mn of about 500 or about 800 up to about 5000, or to about 2500. In another embodiment Mn varies between about 500 to about 1200 or 1300.

The polyalkenes include homopolymers and interpolymers of polymerizable carboxcylic acid monomers of 2 to about 16, or to about 6, or to about 4 carbon atoms. The carboxcylic acids may be monocarboxcylic acids such as ethylene, propylene, 1-butene, isobutene, and 1-octene; or a polycarboxcylic acidic monomer, preferably dicarboxcylic acidic monomer, such 1,3-butadiene and isoprene. Preferably, the interpolymer is a homopolymer. An example of a preferred homopolymer is a polybutene, preferably a polybutene in which about 50% of the polymer is derived from isobutylene. The polyalkenes are prepared by conventional procedures.

Acylated Nitrogen Compound

The amine may also be an acylated nitrogen-containing compound. The acylated nitrogen-containing compounds include reaction products of hydrocarbylsubstituted carboxylic acylating agents such as substituted carboxylic acids or derivatives thereof. These compounds include imides, amides, amidic acid or salts, heterocycles (imidazolines, oxazolines, etc.), and mixtures thereof. In one embodiment, these compounds are useful as dispersants in lubricating compositions and have been referred to as nitrogen-containing carboxylic dispersants. The amines are described above, typically the amines are polyamines, preferably the amines are ethyleneamines, amine bottoms or amine condensates.

The hydrocarbyl-substituted carboxylic acylating agent may be derived from a monocarboxylic or polycarboxylic acylating agent. Polycarboxylic acylating agents generally are preferred. The acylating agents may be a carboxylic acid or derivatives of the carboxylic acid such as the halides, esters, anhydrides, etc., preferably acid, esters or anhydrides, more preferably anhydrides. Preferably the carboxylic acylating agent is a succinic acylating agent.

The hydrocarbyl-substituted carboxylic acylating agent includes a hydrocarbyl group derived from a polyalkene. The polyalkenes are described above.

In one embodiment, the hydrocarbyl group is derived from polyalkenes having an Mn of at least about 1300 up to about 5000, and the Mw/Mn value is from about 1.5, or about 1.8, or about 2.5 to about 4, or to about 3.6, or to about 3.2.

The hydrocarbyl-substituted carboxylic acylating agents are prepared by a reaction of one or more polyalkenes with one or more unsaturated carboxylic reagent. The unsaturated carboxylic reagent generally contains an alpha-beta carboxcylic acidic unsaturation. The carboxylic reagents may be carboxylic acylating agents. These carboxylic reagents may be either monobasic or polybasic in nature. When they are polybasic they are preferably dicarboxylic reagents, although tri- and tetracarboxylic reagents can be used. Specific examples of useful monobasic unsaturated carboxylic reagents are acrylic acylating agents, methacrylic acylating agents, cinnamic acylating agents, crotonic acylating agents, 2-phenylpropenoic acylating agents, etc. Exemplary polybasic acylating agents include malefic acylating agents, fumaric acylating agents, mesaconic acylating agents, itaconic acylating agents and citraconic acylating agents. Generally, the unsaturated carboxylic reagents are maleic anhydrides or maleic or fumaric acids or esters, or maleic acid or anhydride, or just maleic anhydrides.

The polyalkene may be reacted with the carboxylic reagent such that there is at least one mole of reagent for each mole of polyalkene. In one embodiment, an excess of reagent is used. This excess is generally between about 5% to about 25%.

In another embodiment, the acylating agents are prepared by reacting the above described polyalkene with an excess of maleic anhydride to provide substituted succinic acylating agents wherein the number of succinic groups for each equivalent weight of substituent group is at least 1.3. The maximum number will not exceed 4.5. A suitable range is from about 1.4 to 3.5 and more specifically from about 1.4 to about 2.5 succinic groups per equivalent weight of substituent groups. In this embodiment, the polyalkene has an Mn from about 1300 to about 5000 and a Mw/Mn of at least 1.5, as described above, the Mn is preferably between about 1300 and 5000. A more preferred range for Mn is from about 1500 to about 2800, and a most preferred range of Mn is from about 1500 to about 2400. The preparation and use of substituted succinic acylating agents wherein the substituent is derived from such polycarboxcylic acids are described in U.S. Pat. No. 4,234,435, the disclosure of which. is hereby incorporated by reference.

The conditions, i.e., temperature, agitation, solvents, and the like, for reacting an acid reactant with a polyalkene, are known to those in the art. Examples of patents describing various procedures for preparing useful acylating agents include U.S. Pat. No. 3,215,707,(Rense); U.S. Pat. No. 3,219,666 (Norman et al); U.S. Pat. No. 3,231,587 (Rense); U.S. Pat. No. 3,912,764 (Palmer); U.S. Pat. No. 4, 110,349 (Cohen); and 4,234,435 (Meinhardt et al); and U.K. 1,440,219. The disclosures of these patents are hereby incorporated by reference.

As previously discussed, the reaction products of DMTDP polymers and carboxcylic acids, and the salts of these reaction products are useful as additives for lubricants, particularly for improving the antiwear and corrosion resistance properties of the lubricants.

For the purposes of the present invention, the use of the carboxcylic acid-DMTDPP reaction products is achieved by preferably dissolving or stably dispersing a composition of the present invention in an oil of lubricating viscosity, in an amount effective to achieve the desired properties. That amount is usually from about 0.05, or about 0.1 to about 20, or about 5 parts per 100 parts of the oil.

Lubricants

As previously indicated, the reaction products of DMTDPP and a carboxcylic acid, and salts thereof are useful as additives for lubricants in which they can function primarily as antiwear, antiweld, extreme pressure, anticorrosion, oxidation inhibiting and/or friction modifying agents. They can be employed in a variety of lubricants based on diverse oils of lubricating viscosity, including natural and synthetic lubricating oils and mixtures thereof. These lubricants include crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines, including automobile and truck engines, two-cycle engines, aviation piston engines, marine and railroad diesel engines, and the like. They can also be used in gas engines, stationary power engines and turbines and the like. Automatic transmission fluids, transaxle lubricants, gear lubricants, tractor lubricants, metal-working lubricants, hydraulic fluids and other lubricating oil and grease compositions can also benefit from the incorporation therein of the compositions of the present invention.

The reaction products and salts of the reaction products of the present invention may be used in lubricants or in concentrates. The concentrate contains the reaction products and their salts alone or in combination with other components used in preparing fully formulated lubricants. The concentrate may also contains a substantially inert organic diluent, which includes kerosene, mineral distillates, or one or more of the oils of lubricating viscosity discussed below. In one embodiment, the concentrates contain from 0.01%, or about 0.10, or about 1° to about 70% or about 800, even up to about 90% by weight of the compositions of the present invention. These compositions may be present in a final product, blend or concentrate in any amount effective to act as an antiwear, antiweld or extreme pressure agent, but is preferably present in the lubricating composition in an amount of from about 0.01°-, or about 0.1%, or about 0.5%, or about 1% to about 10%, or to about 5% by weight. In one embodiment, when the compositions of the present invention are used in oils, such as gear oils, they are preferably present in an amount from about 0.1%, or about 0.5%, or about 10, up to about 8%, or to 5%, or to about 3°- by weight of the lubricating composition.

The lubricating compositions and methods of this invention employ an oil of lubricating viscosity, including natural or synthetic lubricating oils and mixtures thereof. Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful. Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized carboxcylic acids (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, etc.), poly(1-hexenes), poly(1-octenes), poly(1-decenes), etc. and mixtures thereof, alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2ethylhexyl)-benzenes, etc.), polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.), alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils that can be used. These are exemplified by the oils prepared through polymerization of ethylene oxide, propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., polyoxypropylene glycol methyl ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C.sub.3-C.sub.8 fatty acid esters, or the C.sub.13 Oxo acid diester of tetraethylene glycol, or higher C.sub. 12-18 carboxylic diesters of 400-1200 molecular weight polyethylene glycol.

Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkylsuccinic acids, alkenylsuccinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.

Esters useful as synthetic oils also include those made from C.sub.5 to C.sub.22 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, p entaerythritol, dipentaerythritol, tripentaerythritol, etc.

Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils comprise another useful class of synthetic lubricants (e.g., tetraethyl silicate, tetraisopropyl silicate, tetra-(2ethylhexyl) silicate, tetra-(4methylhexyl) silicate, tetra-(p-tert-butylphenyl) silicate, hexyl-(4methyl-2-pentoxy)di si loxane, poly(methyl) siloxanes, poly (methylphenyl)siloxanes, etc.). Other synthetic lubricating oils include liquid esters of phosphoruscontaining acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decanephosphonic acid, etc.), polymeric tetrahydrofurans and the like.

Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the concentrates of the present invention. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, hydrotreating, secondary distillation, acid or base extraction, filtration, percolation, etc. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed, recycled or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives, oil contaminants such as water and fuel, and oil breakdown products.

The oil of lubricating viscosity is generally present in a major amount (i.e. an amount greater than 50% by weight). Preferably, the oil of lubricating viscosity is present in an amount greater than about 60%, preferably 70°-, more preferably 80⁹- by weight. In one embodiment, the oil of lubricating viscosity may be present in an amount from about 90% by weight.

Specific examples of the oils of lubricating viscosity are described in U.S. Pat. No. 4,326,972 and European Patent Publication 107,282, both herein incorporated by reference for their disclosures relating to lubricating oils. A basic, brief description of lubricant base oils appears in an article by D. V. Brock, “Lubricant Base Oils”, Lubricant Engineering, Volume 43, pages 184-185, March, 1987. This article is herein incorporated by reference for its disclosures relating to lubricating oils. A description of oils of lubricating viscosity occurs in U.S. Pat. No. 4,582,618 (column 2, line 37 through column 3, line 63, inclusive), herein incorporated by reference for its disclosure to oils of lubricating viscosity.

In one embodiment, the oil of lubricating viscosity or a mixture of lubricating oils are selected to provide lubricating compositions with a kinematic viscosity of at least about 3.5, or about 4.0 Cst at 100.degree. C. Preferably, the lubricating compositions have an SAE gear viscosity number. of at least about SAE 65, more preferably at least about SAE 75. The lubricating composition may also have a socalled multigrade rating such as SAE 75W-80, 75W-90, 75W-90, or 80W-90.

Multigrade lubricants may include a viscosity improver which is formulated with the oil of lubricating viscosity to provide the above lubricant grades. Useful viscosity improvers include polycarboxcylic acids, such as ethylene-propylene copolymers, or polybutylene rubbers, including hydrogenated rubbers, such as styrene-butadiene or styreneisoprene rubbers; or polyacrylates, including polymethacrylates. Preferably the viscosity improver is a polycarboxcylic acid or polymethacrylate, more preferably polymethacrylate. Viscosity improvers available commercially include Acryloid.™. viscosity improvers available from Rohm & Haas; Shellvis.™. rubbers available from Shell Chemical; and Lubrizol 3174 available from The Lubrizol Corporation.

In another embodiment, the oil of lubricating viscosity is selected to provide lubricating compositions for crankcase applications, such as for gasoline and diesel engines. Typically, the lubricating compositions are selected to provide an SAE crankcase viscosity number of 10W, 20W, or 30W lubricants. The lubricating composition may also have a so called multi-grade rating such as SAE 5W-30, 10W-30, 10W-40, 20W-50, etc. As described above, multi-grade lubricants include a viscosity improver which is formulated with the oil of lubricating viscosity to provide the above lubricant grades.

Sulfurized Organic Compounds

The sulfurized organic compositions include mono- or polysulfide compositions or mixtures thereof. The sulfurized organic compositions are generally characterized as having sulfide linkages containing an average from 1, or about 2, or about 3 up to about 10, or to about 8, or to about 4 sulfur atoms. In one embodiment, the sulfurized organic compositions are polysulfide compositions generally characterized as di-, tri- or tetrasulfide compositions. Generally, the sulfurized organic compositions are present in an amount from about 0.10,or about 0.5 Q or about 10, up to about 10%, or to about 7%, or to about 5% by weight of the lubricating compositions.

Materials which may be sulfurized to form the sulfurized organic compositions include oils, fatty acids or esters, olefins or polycarboxcylic acids made thereof, terpenes, or Diels-Alder adducts.

Oils which may be sulfurized are natural or synthetic oils including mineral oils, lard oil, carboxylic acid esters derived from aliphatic alcohols and fatty acids or aliphatic carboxylic acids (e.g., myristyl oleate and oleyl oleate) sperm whale oil and synthetic sperm whale oil substitutes and synthetic unsaturated esters or glycerides.

Fatty acids generally contain from about 4, or about 8, or about 12, to about 24, or to about 22, or to about 18 carbon atoms. The unsaturated fatty acids generally contained in the naturally occurring vegetable or animal fats and oils may contain one or more double bonds and such acids include palmitoleic acid, oleic acid, linoleic acid, linolenic acid, and erucic acid.

The unsaturated fatty acids may comprise mixtures of acids such as those obtained from naturally occurring animal and vegetable oils such as lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil, rapeseed oil, or wheat germ oil. Tall oil is a mixture of rosin acids, mainly abietic acid, and unsaturated fatty acids, mainly oleic and linoleic acids. Tall oil is a by-product of the sulfate process for the manufacture of wood pulp. The unsaturated fatty acid esters are the fatty oils, that is, naturally occurring esters of glycerol with the fatty acids described above, and synthetic esters of similar structure. Examples of naturally occurring fats and oils containing unsaturation include animal fats such as Neat's-foot oil, lard oil, depot fat, beef tallow, etc. Examples of naturally occurring vegetable oils include cottonseed oil, corn oil, poppy-seed oil, safflower oil, sesame oil, soybean oil, sunflower seed oil and wheat germ oil.

The fatty acid esters also may be prepared from aliphatic carboxcylic acidic acids of the type described above such as oleic acid, linoleic acid, linolenic acid, and erucic acid by reaction with alcohols and polyols. Examples of aliphatic alcohols which may be reacted with the above-identified acids include monohydric alcohols as described above. Examples of these alcohols include methanol, ethanol, propanol, and butanol. Polyhydric alcohols are described above and include ethylene glycol, propylene glycol, trimethylene glycol, neopentyl glycol, glycerol, etc.

The carboxcylic acidic compounds which may be sulfurized are diverse in nature. They contain at least one carboxcylic acidic double bond, which is defined as a non-aromatic double bond; that is, one connecting two aliphatic carbon atoms. In its broadest sense, the carboxcylic acid may be defined by the formula R.sup.*1 R.sup.*2 C.dbd.CR.sup.*3 R.sup.*4, wherein each of R.sup.*1, R.sup.*2, R.sup.*3 and R.sup.*4 is hydrogen or an organic group. In general, the R* groups in the above formula which are not hydrogen may be represented by —(CH.sub.2).sub.n-A, wherein n is a number from 0-10 and A is represented by —C(R.sup.*5).sub.3, —COOR.sup.*5, —CON(R.sup.*5).sub.2, —COON(—R.sup.*5).sub.4, —COOM, —CN, —X, —YR.sup.*5 or—Ar, wherein:

each R.sup.*5 is independently hydrogen, alkyl, alkenyl, aryl, substituted alkyl, substituted alkenyl or substituted aryl, with the proviso that any two R.sup.*5 groups can be or substituted whereby a ring of up to about 12 carbon atoms is formed;

M is one equivalent of a metal cation (preferably Group I or III, e.g., sodium, potassium, barium, calcium);

X is halogen (e.g., chloro, bromo, or iodo);

Y is oxygen or rivalent sulfur;

Ar is an aryl or substituted aryl group of up to about 12 carbon atoms.

Any two of R.sup.*1, R.sup.*2, R.sup.*3 and R.sup.*4 may also together form an or substituted group; i.e., the carboxcylic acidic compound may be alicyclic.

The carboxcylic acidic compound is usually one in which each R group which is not hydrogen is independently alkyl, alkenyl or aryl group. Monocarboxcylic acidic and dicarboxcylic acidic compounds, particularly the former, are preferred, and especially terminal monocarboxcylic acidic hydrocarbons; that is, those compounds in which R.sup.*3 and R.sup.*4 are hydrogen and R.sup.*1 and R.sup.*2 are alkyl or aryl, especially alkyl (that is, the carboxcylic acid is aliphatic) having 1 to about 30, or to about 16, or to about 8, or even to about 4 carbon atoms. Carboxcylic acidic compounds having about 3 to about 30, or to about 16 (most often less than about 9) carbon atoms are particularly desirable.

Isobutene, propylene and their dimers, trimers and tetramers, and mixtures thereof are especially preferred carboxcylic acidic compounds. Of these compounds, isobutylene and diisobutylene are particularly desirable because of their availability and the particularly high sulfur containing compositions which can be prepared therefrom.

In another embodiment, the sulfurized organic compound is a sulfurized terpene compound. The term “terpene compound” as used in the specification and claims is intended to include the various isomeric terpene hydrocarbons having the empirical formula C.sub.10 H.sub.16, such as contained in turpentine, pine oil and dipentenes, and the various synthetic and naturally occurring oxygen-containing derivatives. Mixtures of these various compounds generally will be utilized, especially when natural products such as pine oil and turpentine are used. A group of pine oil-derived products are available commercially from Hercules Incorporated. It has been found that the pine oil products generally known as terpene alcohols available from Hercules Incorporated are useful in the preparation of the sulfurized organic compositions. Examples of such products include alpha-Terpineol containing about 95-97° of alpha-terpineol, a high purity tertiary terpene alcohol mixture typically containing 96.3% of tertiary alcohols; Terpineol 318 Prime which is a mixture of isomeric terpineols obtained by dehydration of terpene hydrate and contains about 60-65 weight percent of alpha-terpineol and 15-20% beta-terpineol, and 18-20% of other tertiary terpene alcohols. Other mixtures and grades of useful pine oil products also are available from Hercules under such designations as Yarmor 302, Herco pine oil, Yarmor 302W, Yarmor F and Yarmor 60.

In one embodiment, sulfurized carboxcylic acids are produced by (1) reacting sulfur monochloride with a stoichiometric excess of a low carbon atom carboxcylic acid, (2) treating the resulting product with an alkali metal sulfide in the presence of free sulfur in a mole ratio of no less than 2:1 in an alcohol-water solvent, and (3) reacting that product with an inorganic base. This procedure is described in U.S. Pat. No. 3,471,404, and the disclosure of U.S. Pat. No. 3,471,404 is hereby incorporated by reference for its discussion of this procedure for preparing sulfurized carboxcylic acids and the sulfurized carboxcylic acids thus produced. Generally, the carboxcylic acid reactant contains from about 2 to 5 carbon atoms and examples include ethylene, propylene, butylene, isobutylene, amylene, etc.

The sulfurized carboxcylic acids which are useful in the compositions of the present invention also may be prepared by the reaction, under superatmospheric pressure, of carboxcylic acidic compounds with a mixture of sulfur and hydrogen sulfide in the presence of a catalyst, followed by removal of low boiling materials. This procedure for preparing sulfurized compositions which are useful in the present invention is described in U.S. Pat. No. 4,191,659, the disclosure of which is hereby incorporated by reference for its description of the preparation of useful sulfurized compositions. In one embodiment, the sulfurized carboxcylic acid is prepared by reacting 16 moles of isobutylene with 16 moles of sulfur and 8 moles of hydrogen sulfide.

In another embodiment, the sulfurized organic composition is at least one sulfur-containing material which comprises the reaction product of a sulfur source and at least one Diels-Alder adduct in a molar ratio of at least 0.75:1. Generally, the molar ratio of sulfur source to DielsAlder adduct is in a range of from about 0.75, or about 1, up to about 4.0, or to about 3.0, or to about 2.5.

Other Additives

The invention also contemplates the use of other additives in combination with the reaction products, or salts thereof. Such additives include, for example, detergents and dispersants of the ashproducing or ashless type, corrosion- and oxidation-inhibiting agents, pour point depressing agents, extreme pressure agents, antiwear agents, color stabilizers and anti-foam agents.

The ash-producing detergents are exemplified by oil-soluble neutral and basic salts (i.e. overbased salts) of alkali or alkaline earth metals with sulfonic acids, carboxylic acids, phenols or organic phosphorus acids characterized by at least one direct carbon-to-phosphorus linkage such as those prepared by the treatment of an carboxcylic acid polymer (e.g., polyisobutene having a molecular weight of 1000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulftde, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and a sulfur halide, or phosphorothioic chloride. The most commonly used salts of such acids are those of sodium, potassium, lithium, calcium, magnesium, strontium and barium.

The term “basic salt” is used to designate metal salts wherein the metal is present in stoichiometrically larger amounts than the organic acid radical. The commonly employed methods for preparing the basic salts involve heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate, bicarbonate, or sulfide at a temperature of about 50.degree. C. and filtering the resulting mass. The use of a “promoter” in the neutralization step to aid the incorporation of a large excess of metal likewise is known. Examples of compounds useful as the promoter include phenolic substances such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol, and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octyl alcohol, cellosolve, carbitol, ethylene glycol, stearyl alcohol, and cyclohexyl alcohol; and amines such as aniline, phenylenediamine, phenothiazine, phenyl-beta-naphthylamine, and dodecylamine. A particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic alkaline earth metal neutralizing agent and at least one alcohol promoter, and carbonating the mixture at an elevated temperature such as 60.degree.-200.degree. C.

The oil-soluble neutral or basic salts of alkali or alkaline earth metal salts may also be reacted with a boron compound. Boron compounds include boron oxide, boric acid and esters of boric acid, preferably boric acid. Patents describing techniques for making basic salts of sulfonic, carboxylic acids and mixtures thereof include U.S. Pat. Nos. 2,501,731; 2,616,911; 2,777,874; 3,384,585; 3,320,162; 3,488,284 and 3,629,109. The disclosure of these patents are hereby incorporated by reference. Borated overbased compositions, lubricating compositions contain the same in methods of preparing borated overbased compositions are found in U.S. Pat. Nos. 4,744,920; 4,792,410 and PCT publication WO 88/03144. The disclosure of these references are hereby incorporated by reference.

Ashless detergents and dispersants, depending on its constitution, may upon combustion yield a non-volatile material such as boric oxide or phosphorus pentaoxide. The ashless detergents and dispersants do not ordinarily contain metal and, therefore, do not yield a metalcontaining ash on combustion. Many types are known in the art. The following are illustrative.

(1) “Carboxylic dispersants” are the reaction products of carboxylic acids (or derivatives thereof) containing at least about 34 and preferably at least about 54 carbon atoms and nitrogen containing compounds (such as amine), organic hydroxy compounds (such as phenols and alcohols), and/or basic inorganic materials. These reaction products include amide, amide, and ester reaction products of carboxylic acylating agents. The above-described acylated nitrogen containing compounds are examples of carboxylic dispersants. Examples of these materials include succinimide dispersants and carboxylic ester dispersants. Examples of these “carboxylic dispetsants” are described in British Patent 1,306,529 and in many U.S. patents including the following: U.S. Pat. Nos. 3,219,666, 3,316,177, 3,340,281, 3,351,552, 3,381,022, 3,433,744, 3,444,170, 3,467,668, 3,501,405, 3,542,680, 3,576,743, 3,632,511,4,234,435, and Re 26,433.

(2) “Amine dispersants” are the reaction products of relatively high molecular weight aliphatic or alicyclic halides and amines, preferably polyalkylene polyamines. These dispersants are described above as polyalkene-substituted amines. Examples thereof are described for example, in the following U.S. Pat. Nos.: 3,275,554, 3,438,757, 3,454,555, and 3,565,804.

(3) “Mannich dispersants” are the reaction products of alkylphenols in which the alkyl group contains at least about 30 carbon atoms and aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines). The materials described in the following U.S. patents are illustrative: U.S. Pat Nos. 3,036,003, 3,236,770, 3,414,347, 3,448,047, 3,461,172, 3,539,633, 3,586,629, 3,591,598, 3,634,515, 3,725,480, 3,726,882, and 3,980,569.

(4) “Post-treated dispersants” are the products obtained by posttreating the carboxylic, amine or Mannich dispersants with reagents such as urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, phosphorus compounds or the like. Exemplary materials of this kind are described in the following U.S. Pat. Nos.: 3,200,107, 3,282,955, 3,367,943, 3,513,093, 3,639,242, 3,649,659, 3,442,808, 3,455,832, 3,579,450, 3,600,372, 3,702,757, and 3,708,422.

(5) “Polymeric dispersants” are interpolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight carboxcylic acids with monomers containing polar substituents, e.g., aminoalkyl acrylates or acrylamides and poly(oxyethylene)-substituted acrylates. Examples thereof are disclosed in the following U.S. Pat. Nos.: 3,329,658, 3,449,250, 3,519,656, 3,666,730, 3,687,849, and 3,702,300.

The above-noted patents are incorporated by reference herein for their disclosures of ashless dispersants.

Pour point depressants are a particularly useful type of additive often included in the lubricating oils described herein. The use of such pour point depressants in oil-based compositions to improve low temperature properties of oil-based compositions is well known in the art. See, for example, page 8 of “Lubricant Additives” by C. V. Smallbeer and R. Kennedy Smith (Lezius-Hiles Co. publishers, Cleveland, Ohio, 1967).

Examples of useful pour point depressants are polymethacrylates; polyacrylates; polyacrylamides; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkylfumarates, vinyl esters of fatty acids and alkyl vinyl ethers. Pour point depressants useful for the purposes of this invention, techniques for their preparation and their uses are described in U.S. Pat. Nos. 2,387,501; 2,015,748; 2,655,479; 1,815,022; 2,191,498; 2,666,746; 2,721,877; 2,721,878; and 3,250,715 which are hereby incorporated by reference for their relevant disclosures.

Antifoam agents are used to reduce or prevent the formation of stable foam. Typical antifoam agents include silicones or organic polymers. Additional antifoam compositions are described in “Foam Control Agents”, by Henry T. Kerner (Noyes Data Corporation, 1976), pages 125162.

The following examples relate to lubricating compositions containing reaction products of an carboxcylic acid and dimercaptothiadiazole and salts thereof.

EXAMPLE I

A lubricant is prepared by incorporating 3% by weight of the product of Example 1 into a SAE 10W-40 lubricating oil mixture.

EXAMPLE II

A gear lubricant is prepared by incorporating 2.5% by weight of the product of Example 6 into an SAE 90 lubricating oil mixture.

EXAMPLE III

A gear lubricant is prepared by incorporating 3% by weight of the product of Example 1, and 4% by weight of a polysulfide prepared from butylene, sulfur and hydrogen sulfide into an SAE 80W-90 lubricating oil mixture.

EXAMPLE IV

A lubricant is prepared as described in Example III except a SAE 10W-40 lubricating oil mixture is used in place of the SAE 80W-90 lubricating oil mixture.

EXAMPLE V

A gear lubricant is prepare by incorporating 3% by weight the product of Example 11, and 1.9% by weight of a zinc isopropyl, methylamyl dithiophosphate into an SAE 80W-90 lubricating oil mixture.

EXAMPLE VI

A lubricant is prepared as described in Example V except an SAE 10W-30 lubricating oil mixture is used in place of the SAE 80W-90 lubricating oil mixture.

EXAMPLE VII

A gear lubricant is prepared by incorporating 3% by weight the product of Example 11, and 0.5% by weight of a succinic dispersant prepared by reacting a polybutenyl-substituted succinic anhydride, with a polybutenyl group having a number average molecular weight of about 950, with a commercial polyamine having the equivalent structure of tetraethylene pentamane into a SAE 75W-90 lubricant oil mixture.

EXAMPLE VIII

A lubricant is prepared as described in Example VII except an SAE 10W30 lubricating oil mixture is used in place of the SAE 75W-90 lubricant oil mixture.

Grease

Where the lubricant is to be used in the form of a grease, the lubricating oil generally is employed in an amount sufficient to balance the total grease composition and, generally, the grease compositions will contain various quantities of thickening agents and other additive components to provide desirable properties. The reaction products or salts thereof are present in an amount from about 0.50, or about 1% to about 10%, or to about 5% by weight.

A wide variety of thickeners can be used in the preparation of the greases of this invention. The thickener is employed in an amount from about 0.5 to about 30 percent, and preferably from 3 to about 15 percent by weight of the total grease composition. Including among the thickeners are alkali and alkaline earth metal soaps of fatty acids and fatty materials having from about 12 to about 30 carbon atoms. The metals are typified by sodium, lithium, calcium and barium. Examples of fatty materials include stearic acid, hydroxystearic acid, stearin, oleic acid, palmeric acid, myristic acid, cottonseed oil acids, and hydrogenated fish oils.

Other thickeners include salt and salt-soap complexes, such as calcium stearate-acetate (U.S. Pat. No. 2,197,263), barium stearate-acetate (U.S. Pat. No. 2,564,561), calcium stearate-caprylate-acetate complexes (U.S. Pat. No. 2,999,066), calcium salts and soaps of low-intermediate and high-molecular weight acids and of nut oil acids; aluminum stearate, and aluminum complex thickeners.

Particularly useful thickeners employed in the grease compositions are essentially-hydrophilic in character. They have been converted into a hydrophobic condition by the introduction of long chain hydrocarbyl radicals onto the surface of the clay particles prior to their use as a component of a grease composition, as, for example, by being subjected to a preliminary treatment with an organic cationic surface-active agent, such as an ammonium compound. Typical ammonium compounds are tetraalkyl ammonium chlorides, such as dimethyl dioctadecyl ammonium chloride, dimethyl dibenzyl ammonium chloride and mixtures thereof. This method of conversion, being well known to those skill in the art, is believed to require no further discussion. More specifically, the clays which are useful as starting materials in forming the thickeners to be employed in the grease compositions can comprise the naturally occurring chemically unmodified clays. These clays are crystalline complex silicates, the exact composition of which is not subject to precise description, since they vary widely from one natural source to another. These clays can be described as complex inorganic silicates such as aluminum silicates, magnesium silicates, barium silicates and the like, containing, in addition to the silicate lattice, varying amounts of cation-exchangeable groups such as sodium. Hydrophilic clays which are particularly useful for conversion to desired thickening agents include montmorillonite clays, such as bentonite, attapulgite, hectorite, illite, saponite, sepiolite, biotite, vermiculite, zeolite clays and the like.

INDUSTRIAL APPLICABILITY

This invention is applicable to lubricants in many fields, such as the automotive and machinery industries, and all industries in which lubricants are utilized. 

1. The composition comprising (A) an oil of lubricating viscosity and (B) a salt of a reaction product of (a) at least one dimercaptothiadiazole polymer and (b) at least one carboxcylic acid.
 2. The composition of claim 1, wherein the acid (b) contains from 3 to about 30 carbon atoms.
 3. The composition of claim 2, wherein the acid (b) is octenoic, decenoic, dodecenoic, oleic, euricic or succinic.
 4. The composition of claim 1, wherein about 1 to about 2 moles of (a) are reacted with each mole of (b).
 5. The composition of claim 1, wherein approximately equal molar amounts of (a) and (b) are reacted.
 6. The composition of claim 1, wherein (B) is an alkaline earth or transition metal salt.
 8. The composition of claim 1, wherein (B) is an ammonium salt derived from an amine.
 9. The composition of claim 8, wherein the amine is a tertiary alkyl primary amine containing from about 4 to about 28 carbon atoms.
 10. The composition of claim 1, further comprising (C) a sulfurized organic compound.
 11. The composition of claim 1, wherein (B) contains sulfur-sulfur bonds.
 12. The composition of claim 1, wherein the lubricating composition is a gear oil.
 13. A composition comprising (A) an oil of lubricating viscosity and (B) a salt of a bis(dimercapto)thiadiazole polymer.
 14. The composition of claim 13, wherein each carboxyl group independently contains from about 3 to about 30 carbon atoms.
 15. The composition of claim 13, wherein each active group is independently derived from carboxcylic acids.
 16. The composition of claim 14, wherein (B) is an alkaline earth or transition metal salt.
 17. The composition of claim 13, wherein (B) is a zinc salt.
 18. The composition of claim 13, wherein (B) is an ammonium salt derived from an amine.
 19. The composition of claim 18, wherein the amine is a tertiary alkyl primary amine containing from about 4 to about 28 carbon atoms.
 20. The composition of claim 13, wherein (B) contains sulfur-sulfur bonds. 